Rotary snow plow



April 4, 1961 H. HORN 2,977,693

ROTARY SNOW PLOW Filed April 25, 1956 2 Sheets-Sheet 1 INVEN TOR. VA/VS #01? A/ April 4, 1961 H. HORN 2,977,693

ROTARY SNOW PLOW Filed April 23, 1956 2 Sheets-Sheet 2 Fig.5

INVENTOR. HAM 5 f/fi/P/V Un te S s at Q ice ROTARY SNOW PLOW Hans Horn, Liestal, Switzerland, assignor to Schneeraumungsmaschinen AG., Gerlafingen, Switzerland, a company of Switzerland Filed Apr. 23,1956, Ser. No. 579,802 Claims priority, application Switzerland Apr. 2a, 1955 3 Claims. 01. 37-43 surface provided with a discharge opening for the ejection of snow.

Arranged-in front of the wheel in the direction of travel is a cutter designed substantially to loosen and deliver the snow to the ejector wheel. This cutter is accommodated in a housing of square cross section in ac cordance with the cross-sectional area to be cleared. For greater clearing widths, two or more such clearer units are arranged side by side.

These units display a number of disadvantages. Since the housing surrounding the cutter must be forced into the snow as well, which requires considerable force, when the snow is hard or heavy and wet, which the driving vehicle cannot supply, rotary snow. plows of this type are suitable only for clearing fresh, light'snow. It has been attempted to eliminate this disadvantage by arranging the cutter in front of the square housing. Such arrangement, however, causes the snow loosened by the cutter is to be propelled in all directions owing to the absence of an enclosure thereby substantially to obstruct vision. This is particularly noticeable when the height of the snow is less than that of the cutter housing, .acondition obtaining in most clearing work. Moreover the relatively large distance between thecutter and to ejector wheel is a drawback since snow will collect there and form an obstacle for the incoming supplies of 'snow. Particularly with light but cloggy snow, such snow packed between the ejector wheel and the cutter may cause the clearing operation to come to a complete stop.

The rotary snow plow according to the present. invention obviates these disadvantages and is characterized by the fact that the cutter is formed of a number of substantially radial cutting blades of small depth relative to the cutter length, at least the outer portions of thecutter edges of which rotate in different planes in order to increase the space covered by the cutter assembly parallel with the axis of rotation of the cutter.

Embodiments of the invention are shown, by way of example, in the attached drawing in which:

Fig. 1 is a vertical section,

Fig. 2 is a front view of the embodiment of Fig. 1,

Fig. 3 is a side view of a further embodiment,

Fig. 4 is a vertical section through a third embodiment,

Fig. 5 shows a front view of the embodiment of Fig. 4,

Fig. 6 is a detail in section, and

Fig. 7 is a schematic representation of the cutter.

Arranged for rotation in a cylindrical housing 1 (cf. Fig. 1) is an ejector wheel 2 equipped with a number of 8 2,977,693, Patented .Apr- .1961} blades 3. In the housing 1 is an opening connected with a funnel 4. The housing 1 which has a peripheral wall of cylindrical configuration changing into a square frame 5 at its open front end. Rotating within the frame 5 is the cutter 6 holding a plurality of cutting blades 7. The shape of the cutting blades 7 is so designed as to place the outer portions of the cutting edges in several planes. By way of example, in Fig. 1, the outer end of blade 7a is in front of the frame 5, that of blade 711 just within the frame 5 while that of the blade 70 is arranged very near the ejector wheel 2. The number of blades and the position of the blade ends in front of or within the frame 5 may be altered, but the outer portions of the cutting edges must, according to the. invention, rotate in various planes.

Fig. 3 shows a further cutter according to the present invention. The blades are arranged in stepped relationship on the hub so that the cutting edges operate in different planes along their entire length. According to the invention, the cutting edges may alsoenclose an angle with the axis of rotation which is over or below 90.

According to this invention, the depth of the cutting blade 7 is small relatively to its length and it may decrease towards the end. Also the cutting blades are ar ranged to form a cutting angle with respect to their plane of rotation.

It is further possible for the cutting blades to be of unequal lengths and, in particular, for the blade or blades of which the outer portion or portions of the cutting edge rotate in front of the frame 5 to be longer.

The speed of revolution is important for the efiiciencyl of operation of the cutter. For this reason, the inven-i tion provides, besides the normal case in which the ejector wheel and the cutter are arranged on a common shaft and accordingly rotate at the same speed, for ditter ent speeds of revolution of the cutter and of the ejector wheel, the cutter usually rotating at a slower rate thanthe ejector wheel. Fig. 1 is a diagrammatic view of the arrangement of the driving shaft of the cutter 6 within the hollow shaft 9 designed to drive the ejector wheel 2 and arranged in the portion 1a of the housing. The cutter shaft 8 and hollow shaft 9 are driven by a mover accommodated on the driving vehicle via gearing (not shown). The housing 1 has its arms 10 attached to the; driving vehicle (not shown). I

The invention may also he applied to rotary snow; plows in which the rotating cutter performs an additional movement such as described in connection with the embodiment shown in Figs. 4-7, in order to cover an approximately square area. In this embodiment the ejector wheel is rotably arranged in a square housing 11. The ejector wheel consists of a disc 12 and the blades 13 and is driven over the hollow shaft 14 and the gearing 15 by the driving shaft 16. The housing 11 is rigidly connected with the gear casing 17.

Within the hollow shaft 14 a further hollow shaft 18 is journalled which is driven over the gearing 19. A casing 20 is rigidly connected with the hollow shaft 18 and contains a pair of gear wheels 21, 22, driven over a shaft 23 and a gearing 24.

A shaft 25, on which the gear wheel 22'is seated supports with one end a hub 26 of the cutter wheel having three cutting blades 27. The blades 13 extend in a substantially radial direction and their total number may be chosen as desired in contradistinction to that of the cutting blades 27.

It will be noted that the axis of the ejector wheel and of the cutter extend parallel with respect to the longitudinal axis of the machine.

The gear casing 17 is connected to a vehicle 31 by means of arms 29 and the. shaft is driven in an appropriate manner by a prime mover (not shown) located in this vehicle. The housing 11 is provided with a discharge chute through which the snow is ejected by means of the ejector wheel 12, 13.

When removing snow the rotary plow is propelled by the vehicle 31. Simultaneously the shaft 16 is rotated, whereby the two hollow shafts 14 and 18 as well as the shaft 23 are driven over the gearings 15, 19 and 24. By the speed of rotation of the hollow shaft 18 and of the shaft 23, the absolute speed of rotation 11 of the planet wheel 22, of shaft 25 and thereby of the cutter 26, 27 is determined, this speed being n=n +i(n n In this equation n indicates the speed of rotation of shaft 23, 11,; the speed of rotation of the casing 20 forming the carrier of the planetary gear 21, 22 and i the speed ratio between the two gear wheels 21 and 22. If speed ratio and drive characteristics are chosen such that the condition is fulfilled, the ends of the three cutting blades 27 will approximately trace the contour of a square.

Fig. 7 shows schematically the respective positions of the three cutting blades 27 in four different stages corresponding each to a rotation of the cutter about an angle of 90, thereby the ends of the cutting blades are designated IIII and their respective positions 1'4.

By this arrangement it is achieved that the propulsive force to be delivered by the vehicle '31, may be smaller, so that also hard snow may be removed.

It will be understood that the mechanism permitting to cover a square area by the cutter must not necessarily include a gear of the planetary type. The invention enables the range of application of such snow plows to be considerably enlarged. Owing to the fact that the cutting blades of the cutter rotate in different planes, the space between the cutter and the ejector wheel and that in front of the frame is covered. The snow is seized in front of the frame, broken up and moved in the direction towards the ejector wheel. Its path is free from locations where it could collect and it is therefore kept in motion until it reaches the ejector wheel which ejects it through the discharge funnel.

The clearing operation is performed as follows: Both cutter and ejector wheel are set in rotary motion and the snow plow is pushed into the snow by the driving vehicle. The cutter blade rotating in front cuts the snow loose and forces it to the next blade etc. until the rearmost blade delivers it to the ejector wheel which ejects it through the discharge funnel. The small depth of the cutter blades prevent the snow from being forced to the periphery and the snow cannot collect within the frame or housing since the cutting edges, of which at least the outermost portions are axially stepped relatively to one another, cover the entire space. Tests performed with the cutter accordingto thisinvention have given remarkably better results than cutters hitherto employed in that the snow is not propelled away in front of the frame to any substantial extent nor caused to formthe dreaded aggregations between the cutter'and the ejector blade.

What I claim is:

1. A rotary snow plow comprising a housing having a relatively large vertical height and shallow depth with a peripheral wall, back wall and open front, wall means defining a discharge in communication with and extending from said housing, an ejector rotatably mounted in said housing and adjacent said back -wall and having blades extending forwardly in said housing, and a rotary cutter located in front of said ejector having a common central hub and at least three blades connected to said hub at relatively closely spaced locations in an axial direction therealong and extending radially outwardly in angularly spaced directions, said blades being of a size and location to feed snow in the total area adjacent said open front toward said ejector, at least one of said blades having at least its tip portion extending out beyond the open References Cited in the file of this patent UNITED STATES PATENTS 1,274,708 Grabau Aug. 6, 1918 1,577,561 Chiles Mar. 23, 1926 1,594,095 Fey et al. July 27, 1926 1,707,908 Green et al. Apr. 2, 1929 2,360,827 Cole Oct. 24, 1944 2,650,439 Hickman Sept. 1, 1953 FOREIGN PATENTS 286,027 Switzerland Feb. 2, 1953 

